The present invention relates to a process for preparing 2-pyrrolidone which is optionally substituted. Compounds of this type are known and are useful in the preparation of polyamides, like nylon-4, and as a feedstock for preparing (poly)N-vinyl pyrrolidone.
According to published German Application 1,923,063 2-pyrrolidone can be obtained by hydrogenation of succinonitrile (1,2-dicyanoethane) at 80.degree.-200.degree. C. in pyridine or a similar solvent, forming 4-aminobutyronitrile and subsequently treating the aminonitrile at 200.degree.-300.degree. C. with water or an aqueous ammonia solution. The publication states the yield of this reaction procedure to be 72%.
We have now found that 2-pyrrolidone can be prepared from succinonitrile with a higher yield and that, in addition, using the same procedure a substituted succinonitrile can be converted with a good yield into the corresponding substituted 2-pyrrolidone.